According to the book, the transition from being war criminals by day and family men by night, was possible through some rationalisation acrobatics or detachment from responsibility. As an example of detachment, the Nazi concentration camps didn't have an atypical ratio of psychopath to average joe. The predominant "average joes" would offload responsibility by telling themselves that this is not their decision, but that this is the _current policy of the organistation_, which is an interestingly complex statement, in the subconscious sense. It detaches the organisation participant from the organisation, and it detaches the organisation from their policy.
To come back to business v family, I think the old koan holds: separation isn't good. The rule of thumb in social situations is if detachment or separation is the easiest route, you're doing something wrong. Business is social action by necessity. So should we separate action from responsibility? What do we think of someone who is selfish and avoids responsibility?